1. Technical Field
The present invention relates generally to corrosion inhibition for semiconductor devices. More particularly, the present invention relates to an improved method of dicing semiconductor wafers which reduces corrosion of bonding pads.
2. Related Art
It is common in the semiconductor industry to employ aluminum to interconnect structures on integrated circuits and to form the input/output bonding pads. To improve electromigration characteristics and other properties, additives such as copper, e.g. up to 2 percent by weight, or silicon, e.g. up to 1 percent by weight, are typically incorporated into the aluminum conductors. Combinations of aluminum with several of these additives are also known in the art.
After forming the integrated circuits on a wafer, dicing or sawing of the wafer is carried out to provide chips by use of a computer-controlled dicing blade. Because the bonding pads are exposed during dicing operations, they are susceptible to corrosion. One approach to reducing corrosion during dicing, involves the use of high purity deionized water as a coolant for the dicing blade. However, this can lead to a build up of static charge, resulting in accumulation of silicon particles on the bonding pads, as well as contributing to corrosion.
In an effort to address these problems, U.S. Pub. No. US2002/0081776A1 describes affixing a sacrificial anode contacting magnesium to the dicing blade.
Another proposed technique for reducing adherence of silicon particles to bonding pads is described in U.S. Pat. No. 5,461,008, in which the pH of the deionized water is lowered to less than 5.5.
However, there still exists a need in the industry for an improved method for reducing the corrosion of bonding pads on a wafer during dicing, and an improved dicing apparatus for use in practicing the method.